SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8057c924da6a3267d29a8ea1a30133855102b0e918e91532ae443ce4ae65daa5' 
  AND token = 'dF/PFXsfyOs79veEkWHtFYfCW2iGZqMXhIV+57rfYqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}